Reinforced Concrete Structures

What is Reinforced Concrete Structures?

Normally concrete being considerably weak where tension is applied. Therefore, where tension is high concrete will get cracks in its structure. It will reduce the expected strength. In this case, we need to improve the tensile strength of the concrete. Tensile strength of concrete can be increased by adding special components that can resist against the tension. As a result of that, we use reinforcements in concrete structures. It is called Reinforced Concrete Structures. Concrete make a very stable bond with these reinforcements. Reinforced concrete structures are equally good in resisting  both the tension and compression forces.

Reinforced concrete structures are the most common use of any type of construction all around the world ever since it's invented due to its strength and other advantages.

What are the advantages of Reinforced Concrete Structures?

• Strength (can be achieved depending on the application)
• Fire resistant
• Can be casted in any desired shape & size
• Cost effective (cheap compared to other structures)
• Easy Maintenance
• Availability
• Chemical resistance up to a considerable extent 

What are the disadvantages of  Reinforced Concrete Structures?

• Can not be recycled (use for land filling)
• Emission of Carbon Dioxide (CO2)
• Concrete Dust

What are the components in Reinforced Concrete Structures?

• Cement
• Fine Aggregate (Sand)
• Coarse Aggregate (Metal)
• Reinforcement
• Water 

Do you know concrete strength can be achieved depending on the application?

Generally buildings consist of floors, beams, columns, slabs, footings, etc. The requirement of the strength of these components may be different due to different forces and requirements applied on each component. In this case, we can analysis the required strength and requirement then make the structure according to the requirement. It can be done with the proportion of mixing the components that have been mentioned above. In the construction field, we call it the grade of concrete. Normally  reinforcement is used for concrete not less than G20 ( C: S: A = 1:2:4). C = Cement, S = Sand, A = Aggregate

Below the most commonly used concrete grades and it's mixing proportions. But for high rise building and skyscrapers requires a much higher strength of concrete.

• G15 = 1:3:6
• G20 = 1:2:4
• G25 = 1:1 1/2: 3
• G30 = 1:1:3      

Note:
G15 mean it's specified compressive strength at 28 days should be 15 N/mm2. If it is G20 it should achieve 20N/mm2.

How to use reinforcement in concrete structures

We should use reinforcement in concrete structures near the surface as possible. Because the tension is more near the surface. But it should have an allocation to pour minimum size of aggregate to make a proper bond. Not only that but also lessen the chemical reaction and exposure to fire at an event of a fire. Therefore in an extreme weather condition and where fire resistant should be a topic, we should have minimum cover space is little bit spacer to reduce the exposure of reinforcement to the environment.